A longstanding, vexatious problem in the V-belt power transmission art is the need for accurate facial engagement between the side edges of the V-belt and the sidewall faces of the pulley about which the V-belt is trained in the power transmission operation. If the V-belt side faces are not accurately parallel to the pulley groove sidewall faces, increased wear, heat generation, and noise result.
In one form of known power transmission V-belt, the midportion of the belt is formed as a chain, and the side edges are defined by blocks fixedly secured to the sides of the chain portion. It has been found that the outer side surfaces of the blocks secured to the chain portion may not be at the same angle of convergence as the sidewall faces of the pulley groove, and rapid wear of the blocks has resulted. Even more seriously, it has been found that because of insufficient engagement between the blocks and the pulley groove sidewalls, mechanism, such as brakes of the drive system, may not be actuated. Where the load to be transmitted is very high, it has been found that insufficient force transfer between the belt and pulleys results from the incomplete facial engagement so as to preclude proper operation of the power transmission system.
In the conventional V-belt formed of rubber, inaccuracies in the angularity of the side surfaces of the V-belt relative to the sidewall surfaces of the pulley also causes increased wear, heat, and noise. Because the V-belts are formed of a resilient material, such as synthetic resin or rubber, however, they may be caused to accommodate the angular difference by tensioning the belt sufficiently to deform the belt side surfaces into facial engagement with the pulley sidewall surfaces.